But for one big snowstorm in late November, Monday's sleet and ice storm and a cold spell due for New Year's Eve and Day, the Fox Valley, along with a good portion of the eastern United States, has seen a mild winter.

Along with that, though, some locals with knowledge of the Fox River have noticed water levels that have them wary about the potential for flooding.

"The (Fox) water (level) was high before the rain. It's just maintaining at a high level," Elgin Water Director Kyla Jacobsen said. "And yes, there are risks for flooding due to the fact that the ground is saturated, and it's all run-off."

To that end, the National Weather Service on Sunday night posted a flood warning that continues for the Fox River at the Algonquin dam tailwater from Wednesday morning until Sunday afternoon.

"As of 7:30 p.m. Sunday the stage was 8.9 feet, with flood stage at 9.5 feet for that point," the warning stated.

Mike Danahey / The Courier-News

Experts say the Fox River and other bodies of water in Illinois are running high or have already flooded recently with this winter's unusual weather pattern.

Experts say the Fox River and other bodies of water in Illinois are running high or have already flooded recently with this winter's unusual weather pattern. (Mike Danahey / The Courier-News)

Minor flooding is forecast, with the river reaching the flood stage by Wednesday morning and continuing to rise to near 9.6 feet by Wednesday evening, according to the warning. A warning also is in effect for minor flooding Tuesday along the Fox River in Montgomery.

Todd Hoppenstedt, Montgomery director of public works, said he monitored the Fox River levels early Monday where it tends to flow over the banks when the river reaches flood stage.

"The additional 1.5 inches of precipitation that is predicted isn't doing us any favors for the river levels. While the flood stage is 13.0 feet, we don't actually see minor flooding until the river levels actually reaches 14.0 feet," Hoppenstedt said.

Hoppenstedt said in Montgomery the flood-prone stretches along the river are in low lying areas south of the Ashland Bridge and near Mill Street. "We do not anticipate any property flooding but that could change," he said.

What adds to the Fox water levels being high, Jacobsen said, is the dam at McHenry isn't holding water back as would be the case during boating season.

Mike Danahey / The Courier-News

The Fox River is running much higher than usual for December, according to local experts.

The Fox River is running much higher than usual for December, according to local experts. (Mike Danahey / The Courier-News)

Don Bryant, director of the Kane County Office of Emergency Management, reported the Fox River levels "were high" and predicted to reach flood stage by Wednesday.

The National Weather Service in Romeoville anticipated "minor flooding" in the forecast. The NWS indicated the river was originally measured at 12.7 feet and flood stage occurs at 13.0 feet.

Matt Mosteiko, NWS meteorologist, said in the past month the Aurora area has had 4.35 inches of rain.

"We predict an additional one-inch to 1.5 inches of rain tonight," Mosteiko said, adding this will place the rain gauge at around 3.5 inches above normal for the Aurora area.

Bryant did not anticipate major flooding although they are monitoring conditions.

"Fortunately over the past decade there has been work done to mitigate flooding along the shoreline so when the river does reach flood stage, there are not a lot of people affected," Bryant said.

Jim Angel, State Climatologist with the Illinois State Water Survey at the Prairie Research Institute, University of Illinois at Urbana-Champaign said, "Right now the statewide average precipitation for December in Illinois is 4.6 inches, the eighth wettest on record. If we get another inch or so, we could be up to the second wettest on record. Meanwhile, the statewide average temperatures are running almost 12 degrees above average for December, which is on track to being the warmest December on record."

Mike Danahey / The Courier-News

The Fox River's water level is almost up to part of the walking path along its banks in West Dundee.

The Fox River's water level is almost up to part of the walking path along its banks in West Dundee. (Mike Danahey / The Courier-News)

The weather pattern is associated with El Niño, where warm Pacific waters usually mean wetter winters in the West and milder winters in the Midwest and other parts.

"While past strong El Niño events are associated with milder winter temperatures, they have been very inconsistent on winter-time precipitation," Angel said. "Some have been drier, some wetter. For example, comparing the 1982-83 and 1997-98 El Niño events, December 1982 (in Illinois) was the wettest December on record with 7.17 inches, while December 1997 was only 1.91 inches — the 75th wettest December."

According to Angel, perhaps the biggest contribution of the current El Niño to this low-pressure system is that it has been tracking through a much warmer and more moist environment than is usual for late December.

"Temperatures in Illinois have been 17 degrees above average in the last seven days," Angel said. "It reminds me more of a typical March or April storm system in its nature. As a result, for Illinois the system has produced all rain and lots of it."

Local environmentalist and retired high school teacher Gary Swick said that, anecdotally, with the warm weather the Fox River has been free flowing and also seems unusually high.

Swick also noted that he has been taking water samples from the creeks that are tributaries of the Fox west of Elgin for about three years.

"Those creeks are the highest I have ever seen them," Swick said.

As such, Swick said he check United States Geological Survey information online and it appeared that for about the last 17 years — but for numbers recorded in 2009 — the local river and creek levels are well above the mean and in many cases higher than they have been for this time of year.

Jim Slowikowski, a field coordinator with the Illinois State Water Survey, said the stream levels are high across the state. In fact, Slowikowski said he had been in the St. Louis area over the weekend where there had been flooding issues.

According to reports, Interstate 70 was closed for a time in both directions in and out of St. Louis Monday due to flooding issues along the Mississippi River. Near Patooka, Ill., about 60 miles east of St. Louis, five people died Sunday, including two children, after a flooded creek swept away the car in which they were traveling.

Reports had flooding widespread across the southern part of the state, and Slowikowski said some creeks had flooded and roads closed because of standing water in the Champaign area.

Slowikowski had been involved with the Fox River Water Study Group Project. As Elgin's Jacobsen also noted, Slowikowski said, "The Fox is a highly controlled river, from McHenry on down."

Both Slowikowski and Swick agreed that with an already-high river, if there is an extended cold snap that freezes the river, given the right conditions, ice dam issues could cause flooding, too.

"In my years experience in public works I don't think I have ever seen an ice storm quite like this," Hoppenstedt said.

"These are difficult storms when temperatures are at the freezing mark. I almost prefer it to be really cold or well above freezing because snow is easier to deal with then the freezing rain and slush," he said.

Hoppenstedt said it is more difficult to move the heavy accumulating sleet and slush. He said it is harder on the fleet of trucks.

"The rate of the freezing rain has been hard to keep up with — we have every salt truck and plow on the roads and they will continue to be out until we have it under control," the public works director said of the village's seven routes.

Hoppenstedt said crews were spreading salt and calcium chloride during Monday's ice storm.

"With the amount of water on the roadways the salt is diluting faster than if there was snow on the pavement," he said.

"Our crew is used to this kind of work — they are getting along fine. But this kind of storm is hard on the trucks," he said.

Hoppenstedt said the first hint of the icy conditions began around 4 a.m. Monday. "We saw this one coming. I was in contact with my crews throughout the weekend to make sure we were prepared," he said.

He anticipated Montgomery's crews would be out through Monday night.

North Aurora village administrator Steven Bosco rode in one of the village's plows to see firsthand what the conditions were like. He said the village's crews were out early as well.

"The ice storm is a completely different event when crews have to push slush instead of snow as hard surfaces are icing up," Bosco said.

Bosco said he did not anticipate flooding along the Fox River. He said the river generally overflows into North Aurora River Front Park behind Village Hall and North Aurora Island Park near the State Street Bridge.

"If there is any building flooding it could be Village Hall — our basement took in water last spring," the village administrator said.

"The precipitation is predicted to change to all rain. The constant change from ice, snow and rain changes how you attack the system. With temperatures rising overnight that will help," Bosco said.

Slowikowski and Swick also cautioned that if the weather does warm up to be more sunny and spring-like as it had been in parts of December, those who may have received kayaks or other small watercraft should be extra cautious about heading out on the Fox, especially if they are inexperienced.

"With higher water and faster flow, the potential for a mishap goes up," Slowikowski said.

Swick said that ability as well as the quality of the craft should be taken into consideration, not to mention that the water will be very cold increasing the likelihood of hypothermia should someone fall into the river. He also reminded not to boat solo.

"Be very, very cautious," Swick said.

Swick also mentioned that area residents can help prevent or lessen flooding issues in their neighborhoods by making sure storm drains along streets are clear of debris.

And after this storm passes, Angel noted that the National Weather Service forecasts out through January indicate that drier conditions will prevail.

"I have higher confidence in their forecast that temperatures will remain above-average for this winter," Angel said.

A version of this article appeared in print on December 29, 2015, in the News section of the Chicago Tribune with the headline "Flood of worry - Winter weather pattern may lead to flooding woes in Fox Valley" —
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